Sofa



FIG. 1 is a perspective view of the sofa of the present design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a left side elevation view thereof; and,

FIG. 7 is a right side elevation view thereof.

Portion of the sofa shown in broken lines form no part of the claimed design. 

CLAIM The ornamental design for a sofa, as shown and described. 